This invention relates to an improved catalyst for reforming of methanol to hydrogen and carbon monoxide and a process of preparing the same. The catalyst is of the class using a metal of the platinum group as the primary catalytic component.
For use in reforming of methanol to hydrogen and carbon monoxide various catalysts have heretofore been proposed. In one group of such catalysts, a noble metal or a base metal is used as a principal catalytic material which is deposited on a support or carrier made of either active alumina or a silica base oxide. Generally in the catalysts of this category noble metals have been accepted as superior to base metals in terms of both catalytic activity and durability, and some metals of the platinum group such as platinum, palladium and rhodium have been taken as especially advantageous. From a practical point of view, however, these catalysts are still unsatisfactory in their activity, durability and selectivity for the intended decomposition reaction that gives hydrogen and carbon monoxide even when the platinum group metals are used.
In another group of catalysts for reforming of methanol, an oxide of either a rare earth element or a titanium family element is deposited on a carrier which is mainly active alumina precedent to the deposition of a noble metal on the carrier. Lanthanum oxide and cerium oxide are typical examples of the mentioned oxide, and platinum, palladium and/or rhodium are preferred as the catalytic metal also in the catalysts of this group. These catalysts are relatively high in their activity in fresh state and also in the selectivity for the intended decomposition reaction, but they are not yet satisfactory in the activity at relatively low temperatures, durability in the methanol reforming apparatus and adaptability to the reforming processes in which vaporized methanol is passed through a catalyst column at a relatively high space velocity.
In the production of the above described conventional catalysts for the reforming of methanol, it is a common trend to increase the content of the noble metal in order to compensate for the aforementioned shortcomings as far as possible. However, this compensative measure is of limited effect and inevitably leads to a considerable rise in the cost of the catalysts, which imposes a great burden on the reforming of methanol as an industrial process.